Does all power amp sounded the same?
DO we need more power to drive our belove Axiom?

I think many of us asked these question before and some might agreed and some don't.

Me and a few audio fanatic (and bass nuts) did a power amp test at my place, comparing 3 different amp for the front 3 channel of M60v2 and VP150v2

The amp are:-
1. Emotiva XPA-3 (200W/ch)
2. Odessey HT-3 SE (150W/ch)
3. Anthem PVA5 (125W/ch)



All of us (6 of us) agreed that the Odessey sound best with great dynamic and much more refine sound and detail.

The anthem have a better detail than XPA3 but due to it lesser power, the dynamic of the sound somehow are a lot flatter than the other two. And thus not good for movies.

The XPA 3 have the same dynamic (with lots of headroom) as compared with the HT3, but the sound is more metalic and edgy and also lose out the detial to the Anthem and HT3.

And yes, we agreed that amp do sound differently and we need as much power as possible to get most out of the speakers.

We tested scene from Star Wars' "Pod Race" and many concert songs.

Now, please don't fight :p

Michael, the facts of audio technology, which would be confirmed in a properly controlled blind listening test, are that there's no audible difference in either the quality or quantity of power available from those three amplifiers.

Oh, there's going to be a fight.

Get out the canned deer and popcorn!

I thought I heard some metallic sound during the iron giant. Must be the XPA-3. It did feel 'edgy'.

Makes sense, no?

I love the new avatar. Got a laugh out of that one.

See, John, I've been right all along!..... :~)


It says so right here on the interweb...

Good stuff. For another get together, test out some different brands of AVR's with different speaker/room correction programs. Use them as pre-amps if possible with external amplification with the auto calibration and equalization engaged on the AVR. It would be interesting to see which one would come out on top in your test.

Considering the fact that all three of these amps have a different power output, until you somehow, can get them to output at "exactly" equal moderate volume for your source material and can instantaneously switch between them, any realistic comparison is going to be difficult. I dunno, but, it always comes back to the same old story in these comparisons that if one of them is even slightly louder than the other, to the human ear it is going to be perceived as sounding "better" or at minimum, "different". For that reason alone and considering that this is such mature technology, I, personally, have never bought the idea that there is a "real" audible difference between various brands.

a good quality amplifier does only one thing: make the signal stronger. that's all.

as regards comparative tests, the first thing to make sure of is that the amps MUST be adjusted to put out the same exact voltage with a given sine wave signal. a voltmeter must be used for that.

the brain is very finicky for SPL, but it has a very short memory.

Bacon is delicious.

The design of the amp has a lot to do with how it accomplishes the stronger signal, and what portion of the signal.

A class A amp, amplifies the entire sign wave, and is also the least efficient design.. a class AB amp only amplifies a portion of the sign wave which makes it more efficient than a class A amp, it is also less expensive to manufacture a class AB amp with the same power rating as a comparable class A amp. The Emotiva amp is a AB amp, the Odessey is a A/AB amp, and i could not find out the design of the Anthem, but i would guess is is a AB or some combination design... if the Odessey was operating in class A then that would possibly explain why it sounded the best and had the most dynamics. The Odessey most likely operates in the class A region for the first given % of the power, as you draw more power from it, it then switches to an AB operation, if you guys did not turn the volume up insanely loud the Odessey was probably operating in the class A region during your "testing" which was amplifying the entire sign wave, not a portion of it like the Emotiva is doing and possibly the Anthem as well... If you played all of the amps a higher volume, when all amps would be operating as an AB amplifier then i would guess there would be no discernable difference between them at that point.

when we change the amp, we re-run the Audessey of the Onkyo NR808 (as a pre amp) and all channel are calibrated to 75db using a radioshack SPL meter.

The volume dial on the Onkyo is at -10db all the time.

the problem is the huge delay in between setting each amp up, you need special equipment that you can switch in an instant from one amp to another, for a true blind a/b test.

Yeah, but nothing fries up bacon wraped deer links better than a class A amp. That there is a fact.

As for the topic, pick your side, buy your amp/receiver accordingly, be happy.

STOP TEMPTING ME!

With deer or an avr/amp?

AVR. I have all the deer I can handle, I'm told.

But do all amps taste the same?

I think a double-blind amp listening test should be conducted by a group of blind people. I'm not trying to be funny. I truly think it would be interesting as blind people have a heightened sense of hearing.

I believe you must have intended to say "But does all amps taste the same?"
Either that or the original poster meant "All your base are belong to us"

My apologies. I realize English is not the FP's primary language. I intend only humor.

According to that, you should be the definitive judge of all seating surfaces.

Blind musicians would be even better, but still, who's gonna pick-out the cd's and put 'em in the toaster?

I'll say.

That's why Matt Murdock is an attorney by day, Daredevil by night, and an Axiom contractor on the weekends.

HEHEHE .

I'm not saying you are right or wrong, but how did you come to this conclusion based on the information given by the OP or the specifications given by the manufacturers?

oh boy, here we go....drum role....

Opening a can of Deer....

I had a chance to have venison tonight, but I had already ordered my food before I saw the special.

Wouldn't the design be the largest factor? A v.s. A/B?

not to derail the conversation from Bacon.... mmm...

Watching with interest.

True, but not necessarily the class of operation. What about the devices used, topology, feedback methods, phase and gain margin, output impedance/damping factor, individual distortion harmonics, TIM, IMD, slew rate, dynamic current capability, etc, etc. I guess where I'm going with this is that it's misleading to look at a few specs of two amplifiers, like output power into a given load and THD, and then suggest they will sound the same.

Pass the bacon and the toast.

Sure. Amps are pretty complex devices and there is more to amp than it's power capabilities. You can bet that different amps are not designed exactly the same with the exact same frequency response, input impedance, output impedance, crosstalk, noise floor, distortion etc. These are just a few things that can differentiate the capabilities of one amp from another.

Amps may not behave the same at high power demands either. The Axiom Class D amp for example was able to deliver instantaneous current into any one or combination of its channels when needed.

Precisely!

Andrew, i think your point to a certain degree touches on the difference in view of myself and John...

I am of the philosophy that a top grade power amp with more than enough power (250-500W per channel) is the ideal route to go.

John is a believer that the amps in receivers today are more than powerful enough to power a HT.

I think the fundamental design of the amp is a large part of the end result, as is the components used. With the comparison of a Class A->A/B there is a fundamental difference in the operation between these two designs, everything else held constant. As you know, the Class A amplifies the entire sign wave, while the A/B only amplifies a % of the sign wave.

In my experience, if a component is built with components with a tolerance of +/- < 1%, the product is going to work pretty damn close to the way the the math works out on the computer modeling. This can only be accomplished at a very high cost.

However, if a manufacture uses components +/- 5% or greater the final product will work, but the real world product will not work exactly as the math says it will due to larger component deviations.


Also, the amps that are hugely over built result in each component within the product working at below rated output. Where the smaller products will result in each component (transistor) working at near max output for the same amount of power (near saturation), as a transistor gets closer to saturation the more noise gets introduced into the circuite, no?


I am not saying either me or John are right or wrong... we just have a fundamental difference of opinion on how to accomplish the same task.

With all of that being said, i honestly can not "hear" a difference between a receiver amp, my Marantz amp, or my Krell amps...... the difference i tell is the available amount of power, the need for more power is the reason i ended up with Krell amps...

The Krell amps use components with +/- .05%-.1% i believe....

OOH geez, I had to laugh. good one Mark!

Sure. Receivers can power a majority of home theater systems out there but you have to ask these questions if external amplification can be beneficial. What's your listening room size and distance. Are my speakers efficient? How reactive is the loudspeakers load? Most importantly what are your personal listening preferences? It's not cut and dry.

Cook it a little longer and use a knife.

no, Jason... you want some moisture... over cooked and dry is no good!!!!!!

I thought he was asking for dry.

I don't think so..... he said Not Cut AND dry...

Ok then cook with some beer, makes for ome very tasty NOT DRY venison.

um, if you cook with beer that is WAISTING beer.. cook while drinking beer maybe, but then you will have a Dry version for sure......

Not waisting when it enhances MEAT

And................... Scene!

*80's movie slow clap*

Mark, I believe you mean "seen."

All carbohydrates taste the same. After all, their test results are identical, therefore, they taste identical.

Same for protein. All protein that test the same as to number of calories taste the same. The numbers are the same, ergo, QED.

Now, for you scientific ignoramuses who believe the world is flat and that you think you are able to distinguish between the flavors of different carbs and protein, you're kidding yourselves, I mean look at the numbers and wake up!

remember JohnK, our leader, our scientist, our keeper of the one true audio truth.

Your wrong, Carbs in beer tast MUCH better than Carbs in bread..... .....

i think this is a statement that can not be disproven, even by John...

You are totally incorrect. While all carbohydrates are composed of only three elements -- carbon, hydrogen, and oxygen -- they can be very different. There are four types of carbohydrates (a.k.a. saccharides): monosaccharides, disaccharides, oligosaccharides, and polysaccharides.

The first two are commonly known as simple carbohydrates, or sugars. Guess what? They taste sweet.

The second two are commonly known as complex carbohydrates. They do not taste sweet. Please pick your analogies more carefully -- especially when attempting sarcasm.

Now, you were saying…?

Oh, well then, maybe all watts don't sound the same. If the first watt's no good, who cares how many more like it are lined up behind it.